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RM250 Crankcase Assembly Questions

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Hey Guys--

Couple of questions on my reassembly of the RM250 crankcase:

1) With the crankcase sitting on its side, the transmission spins freely in all the gears. But, in first gear, it sort of binds on itself a bit at a certain spot in the rotation. If I just apply a little upward pressure to the two gears that bind (they are on the clutch shaft as opposed to the drive shaft) they free up and spin. When I put the case right side up (not on its side), it's even less noticeable, but it does still happen a bit. Is this normal? The odd thing is that I didn't even disassemble this shaft as it has clips holding three gears in place, and the two that bind on are this shaft.

2) When putting the cases back together, at about 1/4" apart I needed to start tapping with a mallet. I've tapped it down to a 1/16" or so, but I want to make sure I'm supposed to need to hit/tap it with some force. I assume I am since you need a puller to get them apart, but just want to be sure. The crank spins fine at this point as does the transmission (with my note above). Just keep hitting it?

Thanks,

Nathan

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Yes you are doing fine. The tranny wont be smooth until the cases are together. instead of using a mallet use the bolts for the case halves. Be sure to slightly snug them all a little at a time and occassionally use the rubber mallet to tap the case. Take your time and be weary of how you tighten the bolts.

Good luck

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Thanks Mihylo. The manual says the cases should fit together and that I shouldn't need to use the case half bolts to do so. Is this bad/unrealistic info?

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Yeah, thats because you are supposed to be using a crank puller to tighten the cases. When using the case bolt method you have to be really careful and snug bolts in a criss cross pattern.

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Yeah, thats because you are supposed to be using a crank puller to tighten the cases. When using the case bolt method you have to be really careful and snug bolts in a criss cross pattern.

If not be ready to buy a set of cases.

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Having just done a bottom end on my RM250 (my first!) I know what you are going thru. Only you are probably not the 'tard I am, and during dis-assembly one of the seals ended up on the crank shaft and the f*cking wouldn't go together and it was making me insane. and I stripped two of the case bolts.

after I figured out the problem it wasn't a big deal - but I also highly recommend you get a crank puller - it eliminates that "am I stripping the bolts??" feeling.

http://www.rockymountainatvmc.com/productDetail.do?navType=type&webTypeId=140&navTitle=Tools%2FShop&webCatId=22&keyword=PULLER&prodFamilyId=17166

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Thanks for the feedback all. I was able to get the cases together for the final 1/16" with the case bolts. It went together real smoothly with just a little help from the bolts. Next up is the power valve!

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The part that is tight will be the main bearing on the crank. These are tight on the crank so they dont have any movement in them when running

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